Starting out from a known injection moulding technique, so called sequential injection moulding, which for instance is described in U.S. Pat. No. 4,448,324, according to the present invention, the actual technique is given a brand new utility, i.e. the possibility of providing high hygiene seals and manufacturing techniques for such.
The insight that the sequential injection moulding technique allows the production of transition regions which are unnoticeable for the eye and not at least--in sterile systems --unnoticeable for bacteria and other micro-organisms, such unnoticeable or not existing transitions existing between regions of different injection mouldable materials, means the provision of a wide, new perspective within the technique relating to sealingly joining components.
The technique suggested according to the present invention does also reduce the number of elements otherwise necessary for sealing purposes.